With eight days left to raise the nation’s debt ceiling, Senate Majority Leader Harry Reid (D-Nev.) — with crucial backing from the White House — said he is prepared to begin work on his $2.7 trillion deficit reduction and debt limit plan Monday night.

Reid announced Sunday that he would move on his own framework, following the breakdown of another set of bipartisan talks with Speaker John Boehner (R-Ohio) and Senate Minority Leader Mitch McConnell (R-Ky.). With time ticking down and no “grand bargain” to slash $3 trillion to $4 trillion in sight, Reid believes his plan — which he said would include, among other cuts, $1.2 trillion in discretionary spending cuts, $1 trillion in estimated savings from the drawdown of forces in Iraq and Afghanistan and $100 billion in mandatory savings not attached to entitlement programs — is the best way to avert a government default.

Moments after Reid held a press conference to outline his plan, the White House signed on.

“Sen. Reid’s plan is a reasonable approach that should receive the support of both parties, and we hope the House Republicans will agree to this plan so that America can avoid defaulting on our obligations for the first time in our history. The ball is in their court,” White House spokesman Jay Carney said in a statement. “All the cuts put forward in this approach were previously agreed to by both parties through the process led by the Vice President.”

Carney called Reid’s framework a “meaningful down payment” in addressing the deficit and said it could be used as a starting point to tackling a “balanced approach to deficit reduction that includes additional spending reforms and closing tax loopholes for corporations, millionaires and billionaires” in the future.

In addition to the $2.7 trillion in savings — which Democrats say satisfies Boehner’s requirement that any debt ceiling increase be matched dollar-for-dollar with spending cuts — Reid’s plan also would establish a joint Congressional committee, a 12-member body tasked with making recommendations to Congress on further savings by the end of 2011. Reid initially made such a proposal in talks last week with McConnell on another alternative plan to raise the debt limit, and Boehner included a similar proposal in a dueling offering that he also unveiled Monday.

Reid told reporters he intends to introduce his bill to the floor Monday evening and then begin the time-consuming legislative process in the Senate of holding votes on the provision. It’s unclear, however, if Reid has the votes needed to break a likely filibuster on the plan. Plus, House Republicans are moving forward with their own plan, and McConnell took to the floor Monday to support a framework that he, Reid and Boehner, plus their staffs, had been working on over the weekend, which resembles the House plan.

“This weekend, we offered the president a bipartisan proposal to avoid default so we could have the time we need to put together a serious plan for getting our house in order, and he rejected it out of hand,” McConnell said. “Time is running out. And with all due respect to the president, we have more important things to worry about than getting through the next election.”

Democratic aides and the White House dispute McConnell’s account of how the bipartisan plan fell apart. Reid did present the idea to Obama at the White House on Sunday night, but he, Pelosi and the president agreed that a six-month extension of the debt limit, which Boehner pushed, was a “nonstarter.”

Bipartisan Sunday talks between Boehner, McConnell and Reid centered on a potential two-step plan, but Senate Democrats insisted the Sunday offering from Boehner was different than the proposal the Speaker put forth Monday afternoon.

McConnell, who spent several minutes on the floor Monday in animated conversation with Reid, did not specifically address the Senate Democrat’s plan that was to be released minutes later.

When asked whether he believed he would have the votes to send his plan to the House, Reid said, “I would hope so. I’m giving them what they want.”

Reid also noted that he alerted McConnell to his proposal.

For now, at least, the House and Senate seem intent on pursuing dueling legislative tracks. When asked whether McConnell or his Conference could line up behind the Reid plan, a Senate Republican aide expressed doubts that it could pass the House, even though some of its most contested provisions — such as the $1 trillion in war accounting to boost the total savings in the plan, also appeared in the calculations of the House GOP-approved budget.

“The Reid approach cannot probably pass the House, therefore it’s a nonstarter,” the aide said. “Senate Democrats berated House GOP for passing [Cut, Cap and Balance] and laughed at it, saying it was nonstarter for them. Now, they’re demanding a bill pass through Senate that almost surely cannot make it through the House.”